The cheap cooktop which I got out of curiosity about 15 years ago now, had segmented coils(not only rings, but like pieces of pie), adjusting to the diameter and/or position of the the pot/pan. Had 25cm diameter. And didn't do that on/off thing. I measured that with an 'E-smog-meter', with multicolor LED-bar :-)

And that was an entry level thing, equivalent to the stuff you'd get at Ikea for about 50 to 60 bucks now. Mine was €25.

And still working, when I'm back where I lived at the time.

Can you share a link? I’d love to get one. Haven’t found anything like that on the US market.